Frost Advisory
Starts in 39 min
When
From midnight tonight to 9 AM EDT Saturday.
Where
Portions of central, northern, and southern New Jersey and southeast Pennsylvania.
Issued for this forecast zone · National Weather Service Mount Holly NJ
What, impacts and precautionsHide details
What
Temperatures as low as 33 degrees will result in frost formation.
Impacts
Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered.
Precautionary actions
Take steps now to protect tender plants from the cold.
Areas: Middlesex; Western Monmouth; Mercer; Salem; Gloucester; Camden; Northwestern Burlington; Ocean; Cumberland; Atlantic; Southeastern Burlington; Delaware; Philadelphia; Eastern Chester; Eastern Montgomery; Lower Bucks
See it on weather.gov (opens in a new tab)

Observed 9:54 PM EDT at KPNE

Bryn Athyn, PA weather

Clear and 46°8°.

Forecasts agree

Now 46°8°

Clear

Wind: Calm; Up to 5 mph8 km/h through 11 AM
Dew point: 35°2°; Comfortable
UV tomorrow: 4Moderate; Moderate 11 AM–4 PM · peak 4
Air quality: 49Good; Main pollutant: PM2.5 (fine particles)
Pressure: 30.47 inHg1032 hPa; Rising slowly · +0.02 inHg+0.8 hPa in 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

Good hours for

Low 35°2° tomorrow at 6 AM
Above 50°10° tomorrow by 10 AM
High 63°17° tomorrow at 4 PM
Drops 12°7° tomorrow night 6–9 PM (60°16° → 48°9°)
Below 50°10° tomorrow night after 8 PM

TonightDown to 37°3° by 3 AM · Clear
Tomorrow morningUp to 55°13° by 11 AM · Partly cloudy
Tomorrow afternoonUp to 63°17° by 4 PM · Clear
Tomorrow nightDown to 36°2° by 4 AM · Clear
Sunday morningUp to 57°14° by 11 AM · Clear
Sunday afternoonUp to 66°19° by 4 PM · Clear
Sunday nightDown to 46°8° by 10 PM · Clear

Hourly forecast, next 48 hours, in the place's local time
Hour	Conditions	Temperature	Feels like	Precipitation	Wind	Humidity	Cloud cover	UV index
Fri 11p	Mostly clear	41°5° (likely 41°5° to 46°8°)	41°5°	0%	0 mph0 km/h, gusts 4 mph7 km/h	82%	43%	0
Sat 12a	Clear	40°4° (likely 40°4° to 45°7°)	40°4°	0%	0 mph0 km/h, gusts 3 mph5 km/h	85%	9%	0
Sat 1a	Clear	39°4° (likely 39°4° to 44°7°)	39°4°	0%	0 mph0 km/h, gusts 3 mph6 km/h	85%	3%	0
Sat 2a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	0 mph0 km/h, gusts 4 mph6 km/h	85%	0%	0
Sat 3a	Clear	37°3° (likely 37°3° to 43°6°)	37°3°	0%	0 mph0 km/h, gusts 4 mph7 km/h	89%	2%	0
Sat 4a	Clear	37°3° (likely 37°3° to 41°5°)	37°3°	0%	0 mph0 km/h, gusts 5 mph8 km/h	89%	13%	0
Sat 5a	Partly cloudy	37°3° (likely 37°3° to 40°4°)	37°3°	0%	5 mph8 km/h from N, gusts 5 mph8 km/h	89%	50%	0
Sat 6a	Partly cloudy	35°2° (likely 35°2° to 40°4°)	35°2°	0%	5 mph8 km/h from N, gusts 6 mph9 km/h	96%	59%	0
Sat 7a	Mostly sunny	36°2° (likely 36°2° to 40°4°)	36°2°	0%	5 mph8 km/h from N, gusts 6 mph10 km/h	92%	33%	0
Sat 8a	Mostly sunny	38°3° (likely 38°3° to 40°4°)	36°2°	0%	5 mph8 km/h from N, gusts 6 mph10 km/h	85%	31%	0
Sat 9a	Mostly sunny	43°6° (likely 43°6° to 46°8°)	41°5°	0%	5 mph8 km/h from N, gusts 7 mph11 km/h	76%	23%	1
Sat 10a	Mostly sunny	51°11° (likely 49°9° to 52°11°)	51°11°	0%	5 mph8 km/h from N, gusts 6 mph10 km/h	59%	24%	2
Sat 11a	Sunny	55°13° (likely 54°12° to 57°14°)	55°13°	0%	5 mph8 km/h from NE, gusts 5 mph9 km/h	51%	4%	3
Sat 12p	Sunny	58°14° (likely 57°14° to 60°16°)	58°14°	0%	0 mph0 km/h, gusts 4 mph7 km/h	44%	6%	4
Sat 1p	Sunny	61°16° (likely 59°15° to 61°16°)	61°16°	0%	0 mph0 km/h, gusts 4 mph6 km/h	38%	9%	4
Sat 2p	Sunny	62°17° (likely 60°16° to 62°17°)	62°17°	0%	0 mph0 km/h, gusts 3 mph6 km/h	36%	10%	4
Sat 3p	Sunny	62°17° (likely 61°16° to 63°17°)	62°17°	0%	0 mph0 km/h, gusts 4 mph6 km/h	36%	7%	3
Sat 4p	Sunny	63°17° (likely 61°16° to 63°17°)	63°17°	0%	0 mph0 km/h, gusts 4 mph7 km/h	35%	3%	2
Sat 5p	Sunny	62°17° (likely 59°15° to 62°17°)	62°17°	0%	0 mph0 km/h, gusts 4 mph6 km/h	36%	0%	1
Sat 6p	Clear	60°16° (likely 55°13° to 60°16°)	60°16°	0%	0 mph0 km/h, gusts 4 mph6 km/h	41%	0%	0
Sat 7p	Clear	56°13° (likely 52°11° to 56°13°)	56°13°	0%	0 mph0 km/h, gusts 4 mph6 km/h	47%	0%	0
Sat 8p	Clear	48°9° (likely 48°9° to 52°11°)	48°9°	0%	0 mph0 km/h, gusts 4 mph6 km/h	63%	1%	0
Sat 9p	Clear	46°8° (likely 46°8° to 51°11°)	46°8°	0%	0 mph0 km/h, gusts 4 mph6 km/h	73%	1%	0
Sat 10p	Clear	44°7° (likely 44°7° to 48°9°)	44°7°	0%	0 mph0 km/h, gusts 4 mph7 km/h	82%	3%	0
Sat 11p	Clear	42°6° (likely 42°6° to 46°8°)	42°6°	0%	0 mph0 km/h, gusts 4 mph7 km/h	89%	0%	0
Sun 12a	Clear	40°4° (likely 40°4° to 45°7°)	40°4°	0%	0 mph0 km/h, gusts 5 mph7 km/h	96%	0%	0
Sun 1a	Clear	39°4° (likely 39°4° to 45°7°)	39°4°	0%	0 mph0 km/h, gusts 5 mph9 km/h	100%	0%	0
Sun 2a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	0%	0
Sun 3a	Clear	37°3° (likely 37°3° to 44°7°)	37°3°	0%	0 mph0 km/h, gusts 5 mph7 km/h	100%	0%	0
Sun 4a	Clear	36°2° (likely 36°2° to 43°6°)	36°2°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	0%	0
Sun 5a	Clear	36°2° (likely 36°2° to 42°6°)	36°2°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	1%	0
Sun 6a	Clear	35°2° (likely 35°2° to 41°5°)	35°2°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	3%	0
Sun 7a	Sunny	35°2° (likely 35°2° to 40°4°)	35°2°	0%	0 mph0 km/h, gusts 6 mph9 km/h	100%	4%	0
Sun 8a	Sunny	37°3° (likely 37°3° to 41°5°)	37°3°	0%	0 mph0 km/h, gusts 6 mph9 km/h	100%	4%	0
Sun 9a	Sunny	42°6° (likely 42°6° to 47°8°)	42°6°	0%	0 mph0 km/h, gusts 6 mph10 km/h	89%	0%	1
Sun 10a	Sunny	49°9° (likely 49°9° to 53°12°)	49°9°	0%	0 mph0 km/h, gusts 4 mph7 km/h	68%	2%	2
Sun 11a	Sunny	57°14° (likely 56°13° to 59°15°)	57°14°	0%	0 mph0 km/h, gusts 6 mph10 km/h	55%	3%	3
Sun 12p	Sunny	61°16° (likely 59°15° to 62°17°)	61°16°	0%	0 mph0 km/h, gusts 6 mph9 km/h	46%	4%	4
Sun 1p	Sunny	63°17° (likely 61°16° to 64°18°)	63°17°	0%	0 mph0 km/h, gusts 5 mph8 km/h	41%	3%	4
Sun 2p	Sunny	64°18° (likely 62°17° to 65°18°)	64°18°	0%	0 mph0 km/h, gusts 5 mph8 km/h	38%	2%	4
Sun 3p	Sunny	65°18° (likely 63°17° to 66°19°)	65°18°	0%	0 mph0 km/h, gusts 6 mph9 km/h	37%	2%	3
Sun 4p	Sunny	66°19° (likely 63°17° to 66°19°)	66°19°	0%	0 mph0 km/h, gusts 6 mph10 km/h	36%	3%	2
Sun 5p	Sunny	64°18° (likely 62°17° to 64°18°)	64°18°	0%	0 mph0 km/h, gusts 5 mph9 km/h	40%	2%	1
Sun 6p	Clear	61°16° (likely 58°14° to 61°16°)	61°16°	0%	0 mph0 km/h, gusts 4 mph7 km/h	46%	0%	0
Sun 7p	Clear	56°13° (likely 53°12° to 56°13°)	56°13°	0%	0 mph0 km/h, gusts 5 mph7 km/h	57%	0%	0
Sun 8p	Clear	52°11° (likely 50°10° to 55°13°)	52°11°	0%	0 mph0 km/h, gusts 4 mph7 km/h	69%	1%	0
Sun 9p	Clear	48°9° (likely 47°8° to 57°14°)	48°9°	0%	0 mph0 km/h, gusts 2 mph3 km/h	83%	0%	0
Sun 10p	Clear	46°8° (likely 44°7° to 56°13°)	46°8°	0%	0 mph0 km/h, gusts 3 mph4 km/h	89%	0%	0

Days ahead

Shaded: typical range for these dates (1991–2020)

Today, Oct 23. Partly sunny. High 61°16°, low 35°2°. Typical 65°18° / 48°9°. Dry. Forecasts agree.
1. Overnight
  midnight–6 AM
  Clear, 37°3°
  Dry
Official NWS forecast
Tonight: Areas of frost after midnight. Partly cloudy, with a low around 35. Northeast wind 0 to 5 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
60°16°–62°17°
Low, likely
35°2°–46°8°
Typical high / low
65°18° / 48°9°
Wind
11 mph18 km/h, gusts 26 mph41 km/h
UV peak
4
Tomorrow, Oct 24. Mostly sunny. High 63°17°, low 35°2°. Typical 65°18° / 48°9°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Mostly sunny, 38°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 63°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 48°9°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 36°2°
  Dry
Official NWS forecast
Day: Areas of frost before 10am. Sunny, with a high near 63. East wind 0 to 5 mph.
Night: Patchy frost after 10pm. Clear, with a low around 35. South wind around 0 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
61°16°–63°17°
Low, likely
35°2°–39°4°
Typical high / low
65°18° / 48°9°
Wind
6 mph10 km/h
UV peak
4
Sunday, Oct 25. Sunny. High 66°19°, low 39°4°. Typical 64°18° / 48°9°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 37°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 52°11°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 43°6°
  Dry
Official NWS forecast
Day: Patchy frost before 9am. Sunny, with a high near 66. Northwest wind around 0 mph.
Night: Clear, with a low around 39. Northwest wind around 0 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–66°19°
Low, likely
37°3°–40°4°
Typical high / low
64°18° / 48°9°
Wind
6 mph10 km/h
UV peak
4
Monday, Oct 26. Mostly sunny. High 68°20°, low 47°8°. Typical 64°18° / 47°8°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 42°6°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 68°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 57°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 52°11°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 68.
Night: Mostly clear, with a low around 47.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
67°19°–69°21°
Low, likely
36°2°–47°8°
Typical high / low
64°18° / 47°8°
Wind
7 mph11 km/h, gusts 17 mph28 km/h
UV peak
4
Tuesday, Oct 27. Mostly sunny. High 65°18°, low 43°6°. Typical 64°18° / 47°8°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 50°10°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 63°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 53°12°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 43°6°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 65.
Night: Partly cloudy, with a low around 43.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
62°17°–66°19°
Low, likely
43°6°–50°10°
Typical high / low
64°18° / 47°8°
Wind
10 mph16 km/h, gusts 24 mph39 km/h
UV peak
4
Wednesday, Oct 28. Cloudy. High 62°17°, low 47°8°. Typical 63°17° / 47°8°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 43°6°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Partly cloudy, 55°13°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 48°9°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 62.
Night: Mostly cloudy, with a low around 47.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
60°16°–64°18°
Low, likely
40°4°–47°8°
Typical high / low
63°17° / 47°8°
Wind
8 mph13 km/h, gusts 20 mph32 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 68°20°, low 50°10°. Typical 63°17° / 46°8°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 67°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 59°15°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 51°10°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 68.
Night: Partly cloudy, with a low around 50.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
64°18°–69°21°
Low, likely
45°7°–50°10°
Typical high / low
63°17° / 46°8°
Wind
8 mph12 km/h, gusts 28 mph45 km/h
UV peak
4
Friday, Oct 30. Sunny. High 69°21°, low 49°9°. Typical 63°17° / 46°8°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 50°10°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 69°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 58°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 49°9°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 69.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
64°18°–73°23°
Low, likely
47°8°–51°11°
Typical high / low
63°17° / 46°8°
Wind
8 mph13 km/h, gusts 23 mph37 km/h
UV peak
4
Saturday, Oct 31. Partly sunny. High 69°21°, low 48°9°. Typical 62°17° / 46°8°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 68°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 57°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 47°9°
  Dry
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
65°18°–72°22°
Low, likely
40°4°–56°13°
Typical high / low
62°17° / 46°8°
Wind
9 mph15 km/h, gusts 23 mph37 km/h
UV peak
4
Sunday, Nov 1. Cloudy. High 67°19°, low 49°9°. Typical 62°17° / 46°8°. Rain 0.01 in0.3 mm, 20% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 66°19°
  20% chance
3. Evening
  6 PM–midnight
  Partly cloudy, 59°15°
  20% chance
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
61°16°–72°22°
Low, likely
45°7°–54°12°
Typical high / low
62°17° / 46°8°
Wind
10 mph15 km/h, gusts 20 mph31 km/h
UV peak
4

10 days15 days30 days

The outlook

Today
Dry, high 61°, low 35°.
Tomorrow
Dry, high 63°, low 35°.
Sunday
Dry, high 66°, low 39°, warming up.
Rest of week
Mostly dry, highs 62–69°.

Want the meteorologists’ reasoning? Read the NWS forecast discussion (PHI) (opens in a new tab)

What changed since yesterday

No meaningful changes from yesterday’s forecast.

Radar

Radar data: NOAA MRMS, rendered by forecast.blue

Radar loads when scrolled into view

Full-screen radar

Rivers

NOAA river gauges within 25 mi

Neshaminy Creek near Langhorne

6.2 mi

Below flood stage

Level: 1.1 ft
Flow: 123 cfs

Forecast peak 1.1 ft Sat 2 AM

Reading from Fri 9:15 PM · NWS gauge page

Delaware River at Burlington (IN MLLW)

11 mi

Below flood stage

Level: 4.0 ft

Forecast peak 9.1 ft Sat 1 AM

Reading from Fri 9:36 PM · NWS gauge page

Schuylkill River at Philadelphia

14 mi

Below flood stage

Level: 6.1 ft
Flow: 1,060 cfs

Forecast peak 6.1 ft Sat 2 AM

Reading from Fri 9 PM · NWS gauge page

Schuylkill River near Philadelphia near 30th Street

14 mi

Below flood stage

Level: 3.3 ft

Forecast peak 4.8 ft Sat 12 AM

Reading from Fri 9:45 PM · NWS gauge page

For your home

What this week’s weather means for heating, cooling, pipes and fresh air.

Heating this week

About 50% less heating than a typical week.

This week 33Typical 66

Heating degree days, base 65°F

Heat-pump hours, next 7 days

h below 47°F: 24
h below 17°F: 0
h below 5°F: 0

47, 17 and 5°F are the test points heat pumps are rated at. About 20 hours are near freezing and damp, when outdoor units defrost more often.

Comfort

Dry air outside (dew point 35°F).

Open the windows?

Sat, 1:00 PM–6:00 PM

Good stretch to open the windows.

Is this typical?

Philadelphia Franklin Institute · official normals 1991–2020 · records 1940–2026

Oct 23, today vs a typical year

Today’s expected high is 4°2° colder than typical.

Last 7 days vs normal

—SunOct 18
—MonOct 19
—TueOct 20
—WedOct 21
—ThuOct 22
—FriOct 23
—SatOct 24

Bryn Athyn weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 49 min; Losing 2 min 25 s a day; shortest Dec 21, 1 h 31 min less
Golden hour: 5:31–6:25 PM; Morning 7:02–7:57 AM
Blue hour: 6:25–6:36 PM; Morning 6:51–7:02 AM; first light 6:51 AM

Stars tonight? Fair

Mostly clear 12–5 AM, but the moon is 95% lit and up.

Moon

Waxing gibbous

95% lit · growing

Today: sets 4:23 AM · rises 4:40 PM
Full moon: Oct 26
New moon: Nov 9

Looking west from Bryn Athyn. A level horizon.Skyline from USGS elevation data, heights drawn up to 6× taller. Sky, sun and moon as they are now.

1 active weather alert

Frost Advisory

Bryn Athyn, PA weather

Next 2 hours

Next 48 hours

Days ahead

The outlook

Today

Tomorrow

Sunday

Rest of week

What changed since yesterday

Radar

Rivers

Neshaminy Creek near Langhorne

Delaware River at Burlington (IN MLLW)

Schuylkill River at Philadelphia

Schuylkill River near Philadelphia near 30th Street

For your home

Heating this week

Heat-pump hours, next 7 days

Comfort

Open the windows?

Is this typical?

Oct 23, today vs a typical year

Last 7 days vs normal

Sun & moon

Sun

Stars tonight? Fair

Moon